#!/bin/sh
#
# SPDX-License-Identifier: BSD-3-Clause
#
# Copyright © 2019 Keith Packard
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above
#    copyright notice, this list of conditions and the following
#    disclaimer in the documentation and/or other materials provided
#    with the distribution.
#
# 3. Neither the name of the copyright holder nor the names of its
#    contributors may be used to endorse or promote products derived
#    from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
# OF THE POSSIBILITY OF SUCH DAMAGE.
#

qemu="qemu-system-riscv32"

# select the program
elf="$1"
shift

archstring=""
# If readelf is installed, we can use the .riscv.attributes section
# in the file to determine required extensions that we need in QEMU.
# This will give us a string such as "rv64i2p0_m2p0_a2p0_f2p0_d2p0_c2p0"
if command -v readelf >/dev/null 2>/dev/null; then
    # LLVM-based toolchains readelf produces different output from GNU, so
    # check --version output first.
    if readelf --version | grep LLVM >/dev/null; then
        archstring=$(readelf --arch-specific "$elf" | grep "Value: rv" | cut -d: -f2)
    else
        archstring=$(readelf --arch-specific "$elf" | grep Tag_RISCV_arch | cut -d: -f2 | tr -d '"')
    fi
fi
if [ -z "$archstring" ]; then
    echo "Could not determine architecture for $elf, is readelf installed?" >&2
    exit 1
fi
if [ "${archstring#*rv64}" != "$archstring" ]; then
    qemu="qemu-system-riscv64"
    cpu="rv64"
elif [ "${archstring#*rv32}" != "$archstring" ]; then
    qemu="qemu-system-riscv32"
    cpu="rv32"
else
    echo "Unknown architecture for $elf: $archstring" >&2
    exit 1
fi
options="$(echo "$archstring" | sed 's/rv[36][24]//' | sed 's/_/ /g' | sed 's/[0-9]p[0-9]\>//g')"

qemu_version="$("$qemu" --version | grep version | sed 's/.*version \([0-9][0-9.]*\).*/\1/')"

cpu="$cpu,mmu=false,pmp=false"

if [ -z "$options" ]; then
    options="$(echo "$elf" | sed 's/.*rv[36][24]\([a-z]*\)_.*$/\1/' | sed 's/\(.\)/\1 /g')"
fi

for o in $options; do
    # Old versions of qemu don't have new extension subsets
    case "$qemu_version" in
        8*|7*)
            case "$o" in
                zmmul)
                    o=m
                    ;;
                zaamo|zalrsc|zawrs)
                    o=a
                    ;;
            esac
            ;;
    esac
    case "$o" in
        zvl*)
            # qemu doesn't list zvl extensions
            ;;
        *)
            cpu="$cpu,$o=true"
            ;;
    esac
done

# qemu enables some options by defualt; we need to explicitly
# disable them when not selected
enabled_options="i h e g m a f d c s u v zifencei zihintpause"

# Add default enabled options for newer qemu versions
case "$qemu_version" in
    8.[01]*|7*)
        ;;
    *)
        enabled_options="$enabled_options zawrs zfa zihintntl"
        ;;
esac

for enabled in $enabled_options; do
    if echo "$options" | grep -q -w $enabled; then
        :
    else
        cpu="$cpu,$enabled=false"
    fi
done

# Map lower case options to upper case for qemu version 8.1 and earlier
case "$qemu_version" in
    8.[01]*|7*)
        cpu="$(echo "$cpu" | sed 's/\<z/Z/g')"
        ;;
esac

# Set the target machine
machine=virt,accel=tcg

# Map stdio to a multiplexed character device so we can use it
# for the monitor and semihosting output

chardev=stdio,mux=on,id=stdio0

# Point the semihosting driver at our new chardev

cmdline="program-name"
input=""
done=0

while [ "$done" != "1" ]; do
    case "$1" in
        --)
            shift
            done=1
            ;;
        -s|"")
            done=1
            ;;
        *)
            cmdline="$cmdline $1"
            case "$input" in
                "")
                    input="$1"
                    ;;
                *)
                    input="$input $1"
                    ;;
            esac
            shift
            ;;
    esac
done

semi=enable=on,chardev=stdio0,arg="$cmdline"

# Point the monitor at the new chardev too

mon=none

# Disable the serial port

serial=none

echo "$input" | $qemu -chardev $chardev -semihosting-config "$semi" -monitor "$mon" -serial "$serial" -machine "$machine" -cpu "$cpu" -kernel "$elf" -nographic "$@" -bios none -m 2G
